The present invention relates to micro-structures. In particular, the present invention relates to biologically compatible micro-structures and method of making the same.
Scaffold-based biological tissue engineering requires the formation of new tissues which is strongly dependent on the three-dimensional (3D) environment provided by the scaffold. Characteristics of the scaffold that can influence the 3D environment includes its composition, its porous architecture, and its biological response to surrounding tissues/cellular media.
U.S. Pat. No. 6,379,962 (hereinafter the '962 patent) discloses a polymer scaffold having an extensively interconnected macroporous network with macropores having microporous struts as walls. The polymer may be a bio-compatible or bio-degradable polymer. The polymer scaffold is prepared by mixing a liquid polymer with particles, precipitating the liquid polymer with a non-solvent for the liquid polymer and dissolving the particles with a solvent to form the macroporous polymer scaffold. The surface of the polymer scaffold may be modified by acid or base treatment, or by collagen or calcium phosphate deposition. However, this polymer as disclosed in the '962 patent requires surface modification with acid or base treatment or by collagen or calcium phosphate deposition. Furthermore, the structure of the polymer is foam-like with disordered pores that are not homogeneous.
U.S. Pat. No. 6,875,442 (hereinafter the '442 patent) discloses a polymer scaffold with an interconnected macroporous network. The polymer scaffold disclosed embodies macropores having a diameter in a range of 0.5-3.5 mm. The polymer scaffold is prepared using a process which combines the techniques of particulate leaching and phase inversion to render a process that provides amplified means by which to control the morphology of the resulting polymer scaffold. However, the structure disclosed by the '442 patent is foam-like with disordered pores that are not homogeneous.
Similar to the '442 patent, U.S. Pat. No. 7,022,522 (hereinafter the '522 patent) discloses a polymer scaffold that includes an interconnected macroporous network. However, the polymer as disclosed in the '522 patent requires multiple steps to manufacture including particulate leaching and phase inversion. Furthermore, the structure is foam-like with disordered pores that are not homogeneous.
U.S. Pat. No. 6,993,406 (hereinafter the '406 patent) discloses a method for forming a three-dimensional biocompatible porous scaffold structure using a solid freeform fabrication technique that can be used as a medical implant into a living organism. Imaging technology and analysis is first used to determine the three-dimensional design required for the medical implant, such as a bone implant or graft, fashioned as a three-dimensional, biocompatible scaffold structure. The technique is used to either directly produce the three-dimensional porous scaffold structure or to produce an over-sized three-dimensional porous scaffold lattice which can be machined to produce the designed three-dimensional porous scaffold structure for implantation. The method disclosed by the '406 patent, however, requires pre-fabrication software and can manufacture bio-compatible ceramics only.
Therefore, it is desirable to provide an ordered 3D biological scaffold that can be manufactured in simple steps with ordered interconnected pores with controlled pore size. Furthermore, it is desirable to have an ordered 3D biological scaffold that can enable specific cell/tissue growth.